The tide is caused by toxic levels of a sea algae called karenia brevis. Massive blooms of the algae, which occurs naturally at low levels in the ocean, have washed ashore up and down the coast of southwestern Florida. The blooms feed on nutrients like fertilisers that wash into coastal seawater, and thrive in water that is a little bit warm, but not too hot.

The dangerous algae harbours a deadly brevetoxin, which is why red tides are animal killers.

Scientists at the Mote Marine Laboratory say this is the worst red tide they have seen in over a decade. Last week, Florida Governor Rick Scott issued a state of emergency for seven Gulf coast counties.

In addition to fish that suffocate due to the brevetoxin, manatees suffer when they nibble on seagrass that’s been contaminated with the chemical. This red tide has already killed an estimated 92 of them since January, according to Florida’s Fish and Wildlife Conservation Commission.

Last-ditch efforts are underway in Florida to save manatees; nearly a dozen have been taken in for first aid at Sea World in Orlando. When it comes to rescuing and treating sick manatees, earlier is better, according to Sea World – if sick manatees are found in the first 24 hours of intoxication, they have a pretty good chance of making a full recovery. Here’s what the situation looks like:

More than 6,300 manatees call Florida home — an impressive comeback since 1991, when there were just around 1,200 of them left. But 540 manatees have been killed already this year, and more than 17% of those deaths have been attributed to the red tide.

Unfortunately, the theme park hasn’t been able to save everyone. Two manatees who were rescued from the red tide have died there so far, the company said.

Manatees aren’t the only ones who get confused in the algae-plagued waters. Infected sea turtles start swimming in circles and can drown if they’re unable to surface to breathe. More than 110 of them have died so far.

Joe Raedle/Getty ImagesVeterinarian Dr. Heather Barron, from the Clinic for the Rehabilitation of Wildlife, cares for a Loggerhead sea turtle that was found washed ashore after becoming sick in the red tide on August 1, 2018 in Sanibel, Florida.